you had a boy best friend kyle and he had a huge crush on you. He was really jealous when he saw you with your boyfriend and decided to lie to you. He always told you, your boyfriend was a bad guy and that he cheated on you multiple times

you were sitting alone with your boyfriend on the rooftop while kyle secretly watched you. As your boyfriend went away to his friends (he kissed your cheek as a good bye what made kyle jealous) kyle sat next to you*

"I saw him cheating again..he‘s bad.."